As title, I'm using Ubuntu 10.04, and my ubuntu kept showing the sign “Ubuntu is running in low-graphics mode”. I've read another question with same topic (http://askubuntu.com/questions/10664/how-do-i-fix-ubuntu-is-running-in-low-graphics-mode ), but the other one is using ATI Radeon X1200. How can I fix the problem? I'm running Ubuntu on a 200GB partition, and the rest of my computer is Windows7. My graphic card is NVIDIA GeForce GT 555M, and my computer is ACER ASPIRE 5951G.

Your graphics card is an Optimus; it means that you have 2 video cards on your notebook. For that technology Nvidia doesn't have support, than the community is making a way to fix these, but is a little buggy in some systems.

First system is Bumblebee, that in my case didn't work out and you will have to Google the way because I don't now how it works properly.